Through electrode of a device substrate

ABSTRACT

A semiconductor unit includes: a first device substrate including a first semiconductor substrate and a first wiring layer, in which the first wiring layer is provided on one surface side of the first semiconductor substrate; a second device substrate including a second semiconductor substrate and a second wiring layer, in which the second device substrate is bonded to the first device substrate, and the second wiring layer is provided on one surface side of the second semiconductor substrate; a through-electrode penetrating the first device substrate and a part or all of the second device substrate, and electrically connecting the first wiring layer and the second wiring layer to each other; and an insulating layer provided in opposition to the through-electrode, and penetrating one of the first semiconductor substrate and the second semiconductor substrate.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation application of U.S. patentapplication Ser. No. 13/713,398, filed Dec. 13, 2012, which claims thebenefit of priority from prior Japanese Priority Patent Application JP2012-008278 filed in the Japan Patent Office on Jan. 18, 2012, theentire content of which is hereby incorporated by reference.

BACKGROUND

The present disclosure relates to a semiconductor unit including, forexample, a plurality of types of semiconductor chips being laminated, amethod of manufacturing the semiconductor unit, a solid-state imagepickup unit, and an electronic apparatus.

Recently, a solid-state image pickup unit, such as a charge coupleddevice (CCD) or a complementary metal-oxide-semiconductor (CMOS) imagesensor, has been proposed, which includes different types ofsemiconductor chips being laminated, for example, as disclosed inJapanese Unexamined Patent Application Publication No. 2010-245506(JP2010-245506A). In the solid-state image pickup unit ofJP2010-245506A, two types of semiconductor chips are bonded together,and connection pads provided on the chips are then electricallyconnected to each other with through-electrodes. Specifically, athrough-electrode is provided for each pad of the chips, and an embeddedinterconnection is formed by a so-called damascene process forconnection between such through-electrodes.

SUMMARY

In the case where chips are connected to each other with athrough-electrode as described above, the through-electrode as aconductive material is formed penetrating a semiconductor substratesince each chip has a semiconductor substrate including, for example,silicon. As a result, it is difficult to ensure insulation between thethrough-electrode and the semiconductor substrates. In addition, theheight (length) of the through-electrode itself increases, leading to anincrease in wiring capacitance. It is therefore desired to achieve asemiconductor unit allowing excellent electrical connection to beensured between device substrates such as semiconductor chips or wafers.

It is desirable to provide a semiconductor unit allowing excellentelectrical connection to be ensured between different device substrates,a method of manufacturing the semiconductor unit, a solid-state imagepickup unit, and an electronic apparatus.

A semiconductor unit according to an embodiment of the disclosureincludes: a first device substrate including a first semiconductorsubstrate and a first wiring layer, the first wiring layer beingprovided on one surface side of the first semiconductor substrate; asecond device substrate including a second semiconductor substrate and asecond wiring layer, the second device substrate being bonded to thefirst device substrate, and the second wiring layer being provided onone surface side of the second semiconductor substrate; athrough-electrode penetrating the first device substrate and a part orall of the second device substrate, and electrically connecting thefirst wiring layer and the second wiring layer to each other; and aninsulating layer provided in opposition to the through-electrode, andpenetrating one of the first semiconductor substrate and the secondsemiconductor substrate.

A method of manufacturing a semiconductor unit according to anembodiment of the disclosure includes: bonding a first device substrateto a second device substrate, the first device substrate including afirst semiconductor substrate and a first wiring layer, the first wiringlayer being provided on one surface side of the first semiconductorsubstrate, the second device substrate including a second semiconductorsubstrate and a second wiring layer, and the second wiring layer beingprovided on one surface side of the second semiconductor substrate;forming a through-electrode, the through-electrode penetrating the firstdevice substrate and a part or all of the second device substrate andelectrically connecting the first wiring layer and the second wiringlayer to each other; and forming an insulating layer, the insulatinglayer being formed in opposition to the through-electrode andpenetrating one of the first semiconductor substrate and the secondsemiconductor substrate.

In the semiconductor unit and the method of manufacturing thesemiconductor unit according to the above-described respectiveembodiments of the disclosure, the first and second device substratesare bonded to each other, in which the first and second wiring layersare electrically connected to each other by the through-electrode, andthe insulating layer is provided penetrating one of the first and secondsemiconductor substrates. This makes it easier to ensure insulationbetween the semiconductor substrate and the through-electrode. Inaddition, a wiring distance between the first and second wiring layersis reduced, leading to a reduction in wiring capacitance.

A solid-state image pickup unit according to an embodiment of thedisclosure is provided with a semiconductor unit. The semiconductor unitincludes: a first device substrate including a first semiconductorsubstrate and a first wiring layer, the first wiring layer beingprovided on one surface side of the first semiconductor substrate; asecond device substrate including a second semiconductor substrate and asecond wiring layer, the second device substrate being bonded to thefirst device substrate, and the second wiring layer being provided onone surface side of the second semiconductor substrate; athrough-electrode penetrating the first device substrate and a part orall of the second device substrate, and electrically connecting thefirst wiring layer and the second wiring layer to each other; and aninsulating layer provided in opposition to the through-electrode, andpenetrating one of the first semiconductor substrate and the secondsemiconductor substrate.

An electronic apparatus according to an embodiment of the disclosure isprovided with a solid-state image pickup unit. The solid-state imagepickup unit is provided with a semiconductor unit. The semiconductorunit includes: a first device substrate including a first semiconductorsubstrate and a first wiring layer, the first wiring layer beingprovided on one surface side of the first semiconductor substrate; asecond device substrate including a second semiconductor substrate and asecond wiring layer, the second device substrate being bonded to thefirst device substrate, and the second wiring layer being provided onone surface side of the second semiconductor substrate; athrough-electrode penetrating the first device substrate and a part orall of the second device substrate, and electrically connecting thefirst wiring layer and the second wiring layer to each other; and aninsulating layer provided in opposition to the through-electrode, andpenetrating one of the first semiconductor substrate and the secondsemiconductor substrate.

According to the semiconductor unit and the method of manufacturing thesemiconductor unit of the above-described respective embodiments of thedisclosure, the first and second semiconductor substrates are bonded toeach other, in which the first and second wiring layers are electricallyconnected to each other by the through-electrode, and the insulatinglayer is provided penetrating one of the first and second semiconductorsubstrates. As a result, while insulation between the semiconductorsubstrate and the through-electrode is ensured, the wiring capacitancebetween the first and second wiring layers is reduced. Consequently,excellent electrical connection is ensured between different devicesubstrates.

The solid-state image pickup unit and the electronic apparatus accordingto the above-described respective embodiments of the disclosure eachinclude the semiconductor unit according to the above-describedembodiment of the disclosure. As a result, while insulation between thesemiconductor substrate and the through-electrode is ensured, the wiringcapacitance between the first and second wiring layers is reduced.Consequently, excellent electrical connection is established betweendifferent device substrates.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the technology as claimed

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thetechnology.

FIG. 1 is a sectional view illustrating a schematic configuration of asemiconductor unit according to a first embodiment of the disclosure.

FIGS. 2A and 2B are sectional views for describing a method ofmanufacturing the semiconductor unit illustrated in FIG. 1.

FIG. 3 is a sectional view illustrating a step following the steps ofFIGS. 2A and 2B.

FIGS. 4A and 4B are sectional views illustrating steps following thestep of FIG. 3.

FIGS. 5A and 5B are sectional views illustrating steps following thesteps of FIGS. 4A and 4B.

FIG. 6 is a sectional view illustrating a schematic configuration of asemiconductor unit according to a comparative example 1.

FIG. 7 is a sectional view illustrating a schematic configuration of asemiconductor unit according to a comparative example 2.

FIG. 8 is a sectional view illustrating a schematic configuration of asemiconductor unit according to a second embodiment of the disclosure.

FIGS. 9A and 9B are sectional views for describing a method ofmanufacturing the semiconductor unit illustrated in FIG. 8.

FIGS. 10A and 10B are sectional views illustrating steps following thesteps of FIGS. 9A and 9B.

FIG. 11 is a sectional view illustrating a schematic configuration of asemiconductor unit according to a third embodiment of the disclosure.

FIGS. 12A and 12B are sectional views for describing a method ofmanufacturing the semiconductor unit illustrated in FIG. 11.

FIG. 13 is a functional block diagram of a solid-state image pickup unitaccording to application example 1.

FIG. 14 is a schematic diagram for describing a layout of each of apixel section and a circuit section illustrated in FIG. 13.

FIG. 15 is a block diagram illustrating a schematic configuration of anelectronic apparatus (camera) according to application example 2.

DETAILED DESCRIPTION OF EMBODIMENT

Hereinafter, some embodiments of the disclosure will be described indetail with reference to the accompanying drawings. It is to be notedthat description is made in the following order.

-   1. First embodiment (Example of semiconductor unit with    through-electrode formed by electroless plating).-   2. Second embodiment (Example of semiconductor unit with    through-electrode formed by electrolytic plating (time control)).-   3. Third embodiment (Example of semiconductor unit with    through-electrode formed by electrolytic plating (etching after    plating)).-   4. Application example 1 (Example of solid-state image pickup unit).-   5. Application example 2 (Example of electronic apparatus (camera)).

First Embodiment Configuration

FIG. 1 illustrates a sectional configuration of a semiconductor unit(semiconductor unit 1A) according to a first embodiment of thedisclosure. The semiconductor unit 1A, which is used in, for example, asolid-state image pickup unit 1 described later, includes two differenttypes of semiconductor chips (a first chip 10 and a second chip 20)bonded to each other. The first chip 10 has a plurality of pixels eachincluding, for example, an organic photoelectric conversion device, andthe second chip 20 has a peripheral circuit to drive the pixels, asdescribed in detail later. It is to be noted that the first chip 10 andthe second chip 20 correspond to “first device substrate” and “seconddevice substrate”, respectively, in one embodiment of the disclosurewithout limitation.

The first chip 10 includes a semiconductor substrate 12 including amultilayer wiring layer 11 on one surface of the substrate 12, andincluding a device formation layer 13, having a pixel section 10Adescribed later, on the other surface thereof. The second chip 20 alsoincludes a semiconductor substrate 22 including a multilayer wiringlayer 21 on one surface of the substrate 22, and including, for example,a circuit section 130 (not illustrated in FIG. 1) described later on theother surface thereof. For example, the first chip 10 and the secondchip 20 are bonded to each other such that the multilayer wiring layers11 and 21 face each other, for example, with an adhesive layer 14therebetween.

Each of the semiconductor substrates 12 and 22 is formed of, forexample, silicon (Si). The semiconductor substrate, however, may beformed of glass, plastic, or a metal sheet having an insulated surfacedepending on applications of the semiconductor unit 1A.

The multilayer wiring layers 11 and 21 are each configured of aplurality of wiring layers, each including, for example, copper (Cu) oraluminum (Al), provided with interlayer insulating films 11B and 21B,respectively, therebetween. The interlayer insulating films 11B and 21Bare each configured of laminated films such as silicon compound filmsincluding, for example, silicon dioxide (SiO₂), silicon nitride (SiN),and silicon oxynitride (SiON).

The multilayer wiring layers 11 and 21 have pads (a first connection pad11A and a second connection pad 21A, respectively) for electricalconnection between the first and second chips 10 and 20. It is to benoted that the first connection pad 11A and the second connection pad21A correspond to specific but not limitative examples of “first wiringlayer” and “second wiring layer”, respectively, in one embodiment of thedisclosure. The first connection pad 11A and the second connection pad21A are electrically connected to each other by a through-electrode 15provided penetrating the first chip 10 and penetrating part or all ofthe second chip 20. In detail, a through-hole H is provided from thesurface of the first chip 10 up to the surface of the second connectionpad 21A through the device formation layer 13, the semiconductorsubstrate 12, and the multilayer wiring layer 11 (the first connectionpad 11A). A region between the first connection pad 11A and the secondconnection pad 21A in the through-hole H is filled with a conductivefilm, resulting in formation of the through-electrode 15.

The first connection pad 11A and the second connection pad 21A, eachincluding, for example, copper or aluminum, are provided at positionsopposed to each other. The first connection pad 11A has an opening H1 asa part of the through-hole H. The opening H1 is filled with a conductivefilm as the through-electrode 15 for connection to the second connectionpad 21A.

The through-electrode 15 is formed of, for example, copper or nickel(Ni). In the first embodiment, the through-electrode 15 is formed byelectroless plating, as described in detail later. The through-electrode15 has a height (thickness, or wiring distance) of about 3 μm to 15 μm,for example. It is to be noted that the semiconductor unit 1A may haveone through-electrode 15, or two or more through-electrodes 15.

In the first embodiment, an insulating film 16 is further provided onthe through-electrode 15 in the through-hole H. In other words, theinsulating film 16 is so provided as to fill the upper part(corresponding to a region penetrating the semiconductor substrate 12)of the through-hole H.

The insulating film 16 is formed of a highly heat-resistant insulatingmaterial, for example, silicon oxide such as silicon dioxide and siliconoxynitride, or a photosensitive resin such as benzocyclobutene (BCB)resin and polyimide. The surface of the insulating film 16 is coplanarwith the surface of the first chip 10 (the surface of the deviceformation layer 13), and a protective film 17 is so provided as to coverthe insulating film 16 and the device formation layer 13.

The protective film 17 is a monolayer film including, for example, oneof silicon dioxide, silicon nitride, and aluminum oxide, or a multilayerfilm including two or more of them.

[Manufacturing Method]

The semiconductor unit 1A is manufactured in the following way, forexample. FIGS. 2A to 5B illustrate a method of manufacturing thesemiconductor unit 1A in process sequence.

First, as illustrated in FIGS. 2A and 2B, the first and second chips 10and 20 are disposed to be opposed to each other such that the multilayerwiring layers 11 and 21 face each other, and are bonded to each otherwith the adhesive layer 14 therebetween. It is to be noted that thefirst chip 10 includes the multilayer wiring layer 11 in which anopening H1 is beforehand formed in the first connection pad 11A. Thefirst and second chips 10 and 20 may be bonded to each other, forexample, with surface activation treatment instead of the adhesive layer14.

Then, as illustrated in FIG. 3, the through-hole H is formed.Specifically, part of a region opposed to each of the first connectionpad 11A (in detail, the opening H1) and the second connection pad 21A isselectively removed by dry etching using a photolithography process, forexample. Consequently, the device formation layer 13, the semiconductorsubstrate 12, the multilayer wiring layer 11, the adhesive layer 14, aninterlayer insulating film 21B of the multilayer wiring layer 21 areeach partially removed to expose the inner wall (opening H1) of thefirst connection pad 11A and the surface of the second connection pad21A.

Then, as illustrated in FIG. 4A, displacement treatment is performed to(displacement coatings A1 and A2 are formed on) each of the surface ofthe second connection pad 21A and the inner wall surface of the openingH1 of the first connection pad 11A, the surfaces being exposed in thethrough-hole H, as pretreatment for electroless plating described below.In this operation, for example, zinc (Zn) is used for the displacementtreatment for electroless Ni plating, and, for example, palladium (Pd)is used for the displacement treatment for electroless Cu plating.

Then, as illustrated in FIG. 4B, for example, a plated nickel or copperfilm is precipitated in the through-hole H through electroless Ni or Cuplating to form the through-electrode 15, i.e., the first connection pad11A is electrically connected to the second connection pad 21A. In thisoperation, for the electroless Ni plating, a formaldehyde-based platingsolution is applied to fill the through-hole H. For the electroless Cuplating, a sulfonic acid-based plating solution may be used in the sameway. In this operation, the plated film precipitates (grows) from boththe displacement coatings A1 and A2, and the growth rate from each ofthe displacement coatings A1 and A2 is determined based on the area ofeach of the displacement coatings A1 and A2. An area ratio between thedisplacement coatings A1 and A2 may be therefore appropriately setdepending on, for example, an aspect ratio of the through-hole H. Thisprevents the opening H1 from being closed before the first and secondconnection pads 11A and 21A are connected to each other. For example, ifthe opening H has a large aspect ratio (i.e., width<depth), for example,the area of the displacement coating A1 may be set larger than that ofthe displacement coating A2. This advances upward growth of the platingfrom the displacement coating A1. As a result, the first and secondconnection pads 11A and 21A are connected to each other before closingof the opening H1.

Then, the insulating layer 16 is formed. Specifically, first, asillustrated in FIG. 5A, the above-described insulating material isformed over the entire surface of the first chip 10 in such a manner asto fill the region on the through-electrode 15 in the through-hole H.For example, spin on glass (SOG) is formed, for example, by spincoating, and is cured, for example, at a temperature of about 600° C. toform a silicon oxide (SiO₂) film. Alternatively, the photosensitiveresin such as benzocyclobutene (BCB) resin or polyimide may be formed byspin coating, for example. Furthermore, any one of the above-describedsilicon compounds may be deposited by a plasma chemical-vapor-deposition(CVD) process or a high-density plasma CVD (HDP-CVD) process, forexample.

Then, as illustrated in FIG. 5B, the insulating film material formed onthe device formation layer 13 is polished, for example, by a chemicalmechanical polishing (CMP) process to form the insulating layer 16.

Finally, the protective film 17 including the above-described materialis formed, for example, by a CVD process or a sputter process, so thatthe semiconductor unit 1A illustrated in FIG. 1 is completed.

Advantageous Effects

In the semiconductor unit 1A, the two different types of semiconductorchips (the first chip 10 and the second chip 20) are bonded together andare electrically connected to each other by the through-electrode 15,achieving a device having a configuration where the pixel section 10Aand the circuit section 130 are vertically laminated, for example, asdescribed later. In addition, the insulating layer 16 is providedpenetrating the semiconductor substrate 12, thereby making it easier toensure insulation between the semiconductor substrate 12 and thethrough-electrode 15. In addition, a wiring distance between the firstand second wiring layers is reduced, leading to a reduction in wiringcapacitance.

Semiconductor units according to comparative examples of the firstembodiment are now described. FIG. 6 is a sectional view illustrating aschematic configuration of a semiconductor unit according to comparativeexample 1. FIG. 7 is a sectional view illustrating a schematicconfiguration of a semiconductor unit according to comparative example2. In the comparative example 1, as in the first embodiment, differenttypes of chips, or a first chip 100A and a second chip 100B, are bondedto each other, and a first connection pad 1011A and a second connectionpad 1011B provided in multilayer wiring layers 101 and 104,respectively, are electrically connected to each other. In thecomparative example 1, however, the first connection pad 1011A isconnected to the second connection pad 1011B with two through-electrodes107A and 107B. The through-electrode 107A is connected to the firstconnection pad 1011A of the first chip 100A, and the through-electrode107B is connected to the second connection pad 1011B of the second chip100B. In the comparative example 2, as in the first embodiment, thefirst connection pad 1011A is connected to the second connection pad1011B with one through-electrode 109.

In the comparative examples 1 and 2, any of the through-electrodes 107A,107B, and 109 is provided penetrating the semiconductor substrate 102.It is therefore difficult to ensure insulation between thethrough-electrode and the semiconductor substrate 102. In addition, theconfiguration of the comparative example 1 leads to an increase inwiring distance between the first and the second connection pads 1011Aand 1011B, namely, an increase in wiring capacitance. In addition, it isnecessary to form an embedded wiring by a damascene process between thethrough-electrodes 107A and 107B, leading to an increase in number ofprocess steps.

In contrast, in the first embodiment, as described above, while thefirst connection pad 11A is electrically connected to the secondconnection pad 21A by the through-electrode 15, a region penetrating thesemiconductor substrate 12 is filled with the insulating layer 16. Thismakes it easier to ensure insulation between the through-electrode 15and the semiconductor substrate 12. In addition, the distance betweenthe first and the second connection pads 11A and 21A is small comparedwith that in the comparative example 1, allowing a reduction in wiringcapacitance.

In addition, the number of through-electrodes is small compared withthat in the comparative example 1, and wiring formation by a damasceneprocess is eliminated, resulting in a simple manufacturing process.

Furthermore, in the comparative examples 1 and 2, any of thethrough-electrodes 107A, 107B, and 109 penetrates the Si semiconductorsubstrate 12. Hence, if there is a potential difference (for example,about 0 to 200 V) between the through-electrode and the semiconductorsubstrate, current leakage occurs between the through-electrode and thesemiconductor substrate at a relatively low voltage. In the firstembodiment, the through-electrode 15 does not penetrate thesemiconductor substrate 12, preventing such a disadvantage (so-calleddegradation of withstand voltage or insufficient insulation withstandvoltage).

In addition, the insulating layer 16 is formed on the through-electrode15 so as to fill the upper part of the through-hole H. Thus,airtightness of the through-electrode 15 is maintained, and even if thethrough-electrode 15 is subsequently subjected to a high-temperatureprocess, the through-electrode 15 may not be damaged.

As described hereinbefore, in the first embodiment, the first and secondchips 10 and 20 are bonded to each other, in which the first and secondconnection pads 11A and 21A are electrically connected to each other bythe through-electrode 15, and the region penetrating the semiconductorsubstrate 12 is filled with the insulating layer 16. As a result, whileinsulation between the semiconductor substrate 12 and thethrough-electrode 15 is ensured, the wiring capacitance between thefirst and the second connection pads 11A and 21A is reduced.Consequently, excellent electric connection is ensured between differentsemiconductor chips (device substrates).

Second Embodiment Configuration

FIG. 8 illustrates a sectional configuration of a semiconductor unit(semiconductor unit 1B) according to a second embodiment of thedisclosure. The semiconductor unit is used in the solid-state imagepickup unit 1 described later, as in the semiconductor unit 1A of thefirst embodiment. In addition, the first and second chips 10 and 20 arebonded to each other, in which while the first connection pad 11A iselectrically connected to the second connection pad 21A by thethrough-electrode 15, the region penetrating the semiconductor substrate12 on the through-electrode 15 is filled with the insulating layer 16.Furthermore, the protective film 17 is provided over the deviceformation layer 13 of the first chip 10. It is to be noted thatcomponents similar to those in the first embodiment are designated bythe same numerals, and description thereof is appropriately omitted.

The semiconductor unit 1B, however, is different from the semiconductorunit of the first embodiment in that the through-electrode 15 is formedby electrolytic plating, and a seed metal layer A3 (metal thin film) isprovided over the inner wall surface of the through-hole H and thesurface of the second connection pad 21A exposed in the through-hole H.

The seed metal layer A3 is a thin film layer as a seed layer for theelectrolytic plating, and is configured of, for example, a laminatedfilm of tantalum (Ta) and copper, a laminated film of titanium (Ti) andcopper, or a laminated film of a titanium-tungsten alloy (TiW) andcopper. The through-electrode 15 is similar to that in the firstembodiment except for the film-formation process, and also includes, forexample, nickel or copper. The seed metal layer A3 has a thickness ofabout 10 nm to 35 nm, for example.

[Manufacturing Method]

The semiconductor unit 1B is manufactured in the following way, forexample. Specifically, first, in a manner similar to that of the firstembodiment, the first and second chips 10 and 20 are bonded to eachother, and then the through-hole H is formed at a position in oppositionto each of the first connection pad 11A and the second connection pad21A.

Then, as illustrated in FIG. 9A, the seed metal layer A3 is depositedover the entire surface of the substrate by a sputter process, forexample.

Then, as illustrated in FIG. 9B, electrolytic Ni or Cu plating isperformed. In this operation, in the second embodiment, the firstconnection pad 11A is connected to the second connection pad 21A by theplated Ni or Cu film precipitated by the electrolytic plating, and thenthe electrolytic plating is stopped before the plated film fills aregion corresponding to the semiconductor substrate 12 (preferably,immediately after the first connection pad 11A is connected to thesecond connection pad 21A). In this way, the through-electrode 15 in thesecond embodiment is formed through control of a condition (time) of theelectrolytic plating.

Then, the insulating layer 16 is formed. Specifically, first, asillustrated in FIG. 10A, the above-described insulating material isformed over the entire surface of the first chip 10 in such a manner asto fill the region on the through-electrode 15 in the through-hole H, asin the first embodiment. Then, as illustrated in FIG. 10B, theinsulating film material and the seed metal layer A3 formed on thedevice formation layer 13 are polished to be removed, for example, by aCMP process to form the insulating layer 16.

Finally, the protective film 17 including the above-described materialis formed, for example, by a CVD process or a sputter process, so thatthe semiconductor unit 1B illustrated in FIG. 8 is completed.

Advantageous Effects

In the semiconductor unit 1B of the second embodiment, as in thesemiconductor unit 1A of the first embodiment, the first and secondchips 10 and 20 are bonded to each other, in which the first and secondconnection pads 11A and 21A are electrically connected to each other bythe through-electrode 15, and the insulating layer 16 is provided in theregion penetrating the semiconductor substrate 12. As a result, whileinsulation between the semiconductor substrate 12 and thethrough-electrode 15 is ensured, the wiring capacitance between thefirst and the second connection pads 11A and 21A is reduced.Consequently, the same advantageous effects as in the first embodimentare achieved. In addition, even if the through-hole H has a large aspectratio (i.e., depth>diameter), disconnection at a step of the seed metallayer A3 is suppressed, avoiding inferior plating due to suchdisconnection at a step. Furthermore, the plated film is prevented frombeing formed on the surface of the first chip 10 through time control ofelectrolytic plating, making it possible to eliminate the necessity ofperforming a polishing process of the plated film before forming theprotective film 17.

Third Embodiment Configuration

FIG. 11 illustrates a sectional configuration of a semiconductor unit(semiconductor unit 1C) according to a third embodiment of thedisclosure. In the third embodiment, as in the first and secondembodiments, the first connection pad 11A is electrically connected tothe second connection pad 21A by the through-electrode 15, and theregion penetrating the semiconductor substrate 12 on thethrough-electrode 15 is filled with the insulating layer 16 in the firstand second chips 10 and 20. Furthermore, the protective film 17 isprovided over the device formation layer 13 of the first chip 10. It isto be noted that components similar to those in the first embodiment aredesignated by the same numerals, and description thereof isappropriately omitted.

In addition, as in the second embodiment, the through-electrode 15 isformed by electrolytic plating, and the seed metal layer A3 is providedover the inner wall surface of the through-hole H and the surface of thesecond connection pad 21A exposed in the through-hole H. The thirdembodiment, however, is different from the second embodiment in that theseed metal layer A3 is formed only on a region opposed to thethrough-electrode 15 excluding a part, which corresponds to a regionopposed to the insulating layer 16, of the inner wall surface of thethrough-hole H.

[Manufacturing Method]

The semiconductor unit 1C is manufactured in the following way, forexample. Specifically, first, in a manner similar to that of the firstembodiment, the first and second chips 10 and 20 are bonded to eachother, and then the through-hole H is formed at a position in oppositionto each of the first connection pad 11A and the second connection pad21A.

Then, in a manner similar to that of the second embodiment, the seedmetal layer A3 is formed over the entire surface of the substrate, andthen, as illustrated in FIG. 12A, electrolytic Ni or Cu plating isperformed. In this operation, in the third embodiment, the firstconnection pad 11A is connected to the second connection pad 21A by theplated Ni or Cu film precipitated by the electrolytic plating, and thenthe electrolytic plating is further continued until the through-hole His filled. Then, as illustrated in FIG. 12B, the upper part (a regionwhere the insulating layer 16 is to be formed on the first connectionpad 11A) of the plated film filled in the through-hole H is selectivelyremoved by etching using a photolithography process, for example. Inthis operation, a mixed solution (FPM) of hydrofluoric acid (HF),hydrogen peroxide (H₂O₂), and pure water (H₂O) may be used as anetchant. Part of the seed metal layer A3 is also removed together. Inthis way, in the third embodiment, the plated film is etched after theelectrolytic plating process to form the through-electrode 15.

Then, the insulating layer 16 and the protective film 17 are formed inthis order in a manner similar to that in each of the first and secondembodiments, so that the semiconductor unit 1C illustrated in FIG. 11 iscompleted.

Advantageous Effects

In the semiconductor unit 1C of the third embodiment, as in thesemiconductor unit 1A of the first embodiment, the first connection pad11A is electrically connected to the second connection pad 21A by thethrough-electrode 15, and the insulating layer 16 is provided in theregion penetrating the semiconductor substrate 12 on thethrough-electrode 15 in the first and second chips 10 and 20. As aresult, while insulation between the semiconductor substrate 12 and thethrough-electrode 15 is ensured, the wiring capacitance between thefirst and the second connection pads 11A and 21A is reduced.Consequently, the same advantageous effects as in the first embodimentare achieved. In addition, as in the second embodiment, even if thethrough-hole H has a large aspect ratio, inferior plating due todisconnection at a step of the seed metal layer A3 is avoided.Furthermore, inferior filling due to a variation in diameter of thethrough-electrode 15 is avoided.

Application Example 1

FIG. 13 illustrates an overall configuration of a solid-state imagepickup unit (solid-state image pickup unit 1) to which any one of thesemiconductor units 1A to 1C described in the first to third embodimentsis applied. The solid-state image pickup unit 1 is, for example, a CMOSimage sensor that includes a pixel section 10A as an image pickup area,and a circuit section 130 including, for example, a row scan section131, a horizontal selection section 133, a column scan section 134, anda system control section 132.

In the application example 1, as illustrated in FIG. 14, for example,the pixel section 10A is provided in the first chip 10 (the deviceformation layer 13) of each of the semiconductor units 1A to 1C, and thecircuit section 130 is provided in the second chip 20 thereof. Thesystem control section 132, which is not illustrated, of the circuitsection 130 may be provided in the first chip 10 together with the pixelsection 10A.

The pixel section 10A includes a plurality of unit pixels P that aretwo-dimensionally arranged in a matrix, for example. For example, theunit pixels P are connected to pixel drive lines Lread (in detail, rowselection lines and reset control lines) for each of pixel rows, andconnected to vertical signal lines Lsig for each of pixel columns. Eachpixel drive line Lread transmits a drive signal to read a signal from apixel. One end of the pixel drive line Lread is connected to an outputend corresponding to each row of the row scan section 131.

The row scan section 131 is configured of components such as a shiftregister and an address decoder, and serves as a pixel drive sectionthat drives the pixels P in the pixel section 10A in rows, for example.Each of signals, which are output from the pixels P in a pixel rowselectively scanned by the row scan section 131, is supplied to thehorizontal selection section 133 through each vertical signal line Lsig.The horizontal selection section 133 is configured of components such asan amplifier and a horizontal selection switch provided for eachvertical signal line Lsig.

The column scan section 134 is configured of components such as a shiftregister and an address decoder, and scans to sequentially drive thehorizontal selection switches of the horizontal selection section 133.Through such selective scan by the column scan section 134, a signal foreach pixel, which is transmitted through each vertical signal line Lsig,is sequentially output to each horizontal signal line 19, and is thentransmitted to an external unit through the horizontal signal line 19.

The system control section 132 receives a clock from an external unit,data instructing an operation mode, and other signals, and outputs datasuch as internal information of a solid-state image pickup unit 1. Thesystem control section 132 further includes a timing generator thatgenerates various timing signals, and performs drive control of circuitsections such as the row scan section 131, the horizontal selectionsection 133, and the column scan section 134 based on the various timingsignals generated by the timing generator.

Application Example 2

The above-described solid-state image pickup unit 1 may be applied toany type of electronic apparatuses having an image pickup function, forexample, a camera system such as a digital still camera and a videocamcorder, and a mobile phone having an image pickup function. FIG. 15illustrates a schematic configuration of an electronic apparatus 2(camera) as an example of the electronic apparatus. The electronicapparatus 2 is, for example, a video camcorder that may take a still ormoving image, and has the solid-state image pickup unit 1, an opticalsystem (optical lens) 310, a shutter unit 311, a drive section 313 thatdrives the solid-state image pickup unit 1 and the shutter unit 311, anda signal processing section 312.

The optical system 310 guides image light (incident light) from asubject to the pixel section 10A of the solid-state image pickup unit 1.The optical system 310 may be configured of a plurality of opticallenses. The shutter unit 311 controls an application/blocking period oflight to the solid-state image pickup unit 1. The drive section 313controls transfer operation of the solid-state image pickup unit 1 andshutter operation of the shutter unit 311. The signal processing section312 performs various types of signal processing to the signal outputfrom the solid-state image pickup unit 1. An image signal Dout subjectedto the signal processing is stored in a storage medium such as a memory,or output to a display, for example.

Although the technology has been described with the example embodimentsand the application examples, the contents of the disclosure are notlimited thereto, and various modifications or alterations thereof may bemade. For example, although the example embodiments and the applicationexamples have been described with a case where two (two types of)semiconductor chips are bonded to each other, three or moresemiconductor chips may be bonded (laminated) to one another. In such acase as well, the through-electrode is provided to electrically connectthe connection pads of the chips to each other, and the insulating layeris provided penetrating one semiconductor substrate on a surface side,achieving the advantageous effects of the contents of the exampleembodiments of the disclosure.

Although the example embodiments and the application examples have beenexemplified with a configuration of a solid-state image pickup unit of aback-side illumination type, the contents of the disclosure areapplicable to a solid-state image pickup unit of a front-sideillumination type.

In addition, each of the semiconductor unit and the solid-state imagepickup unit according to the disclosure may not include all thecomponents described in the above example embodiments and theapplication examples, or may further include another layer.

Accordingly, it is possible to achieve at least the followingconfigurations from the above-described example embodiments, themodifications, and the application examples of the disclosure.

(1) A semiconductor unit, including:

a first device substrate including a first semiconductor substrate and afirst wiring layer, the first wiring layer being provided on one surfaceside of the first semiconductor substrate;

a second device substrate including a second semiconductor substrate anda second wiring layer, the second device substrate being bonded to thefirst device substrate, and the second wiring layer being provided onone surface side of the second semiconductor substrate;

a through-electrode penetrating the first device substrate and a part orall of the second device substrate, and electrically connecting thefirst wiring layer and the second wiring layer to each other; and

an insulating layer provided in opposition to the through-electrode, andpenetrating one of the first semiconductor substrate and the secondsemiconductor substrate.

(2) The semiconductor unit according to (1), wherein

the first device substrate is laminated on the second device substrate,

the through-electrode fills a region between the first wiring layer andthe second wiring layer in a through-hole, the through-hole penetratingfrom a surface of the first device substrate up to a surface of thesecond wiring layer through the first semiconductor substrate and thefirst wiring layer in this order, and

the insulating layer fills a region on the through-electrode in thethrough-hole.

(3) The semiconductor unit according to (2), wherein the first wiringlayer is apertured as an opening that configures a part of thethrough-hole.

(4) The semiconductor unit according to (2) or (3), wherein an innerwall of the through-hole is entirely covered with a metal thin film.

(5) The semiconductor unit according to (2) or (3), wherein, of an innerwall of the through-hole, only a region opposed to the through-electrodeis covered with a metal thin film.

(6) The semiconductor unit according to any one of (1) to (5), whereinthe through-electrode includes one of copper and nickel.

(7) The semiconductor unit according to any one of (1) to (6), whereinthe insulating layer includes one of a silicon oxide film and aphotosensitive resin.

(8) The semiconductor unit according to any one of (2) to (7), furtherincluding a protective film provided on the first device substrate.

(9) A method of manufacturing a semiconductor unit, the methodincluding:

bonding a first device substrate to a second device substrate, the firstdevice substrate including a first semiconductor substrate and a firstwiring layer, the first wiring layer being provided on one surface sideof the first semiconductor substrate, the second device substrateincluding a second semiconductor substrate and a second wiring layer,and the second wiring layer being provided on one surface side of thesecond semiconductor substrate;

forming a through-electrode, the through-electrode penetrating the firstdevice substrate and a part or all of the second device substrate andelectrically connecting the first wiring layer and the second wiringlayer to each other; and

forming an insulating layer, the insulating layer being formed inopposition to the through-electrode and penetrating one of the firstsemiconductor substrate and the second semiconductor substrate.

(10) The method of manufacturing the semiconductor unit according to(9), further including forming, after the bonding the first devicesubstrate to the second device substrate, a through-hole penetratingfrom a surface of the first device substrate up to a surface of thesecond wiring layer through the first semiconductor substrate and thefirst wiring layer in this order,

wherein the forming the through-electrode includes filling a regionbetween the first wiring layer and the second wiring layer in the formedthrough-hole, and

the forming the insulating layer includes filling, after the forming thethrough-electrode, a region on the through-electrode in thethrough-hole.

(11) The method of manufacturing the semiconductor unit according to (9)or (10), wherein the forming the through-electrode includes performingelectroless plating to form the through-electrode.

(12) The method of manufacturing the semiconductor unit according to(10) or (11), wherein the forming the insulating layer includes:

forming, after the forming the through-electrode and the filling theregion on the through-electrode in the through-hole, a film of aninsulating material over the first device substrate; and

polishing, after the forming the film of the insulating material, thefilm of the insulating material.

(13) The method of manufacturing the semiconductor unit according to (9)or (10), wherein the forming the through-electrode includes performingelectrolytic plating to form the through-electrode.

(14) The method of manufacturing the semiconductor unit according to(13), wherein the forming the through-electrode includes stopping theperforming the electrolytic plating after the first wiring layer and thesecond wiring layer are connected to each other by a plating filmprecipitated in the through-hole but before the through-hole is filledby the plating film.(15) The method of manufacturing the semiconductor unit according to(13), wherein the forming the through-electrode includes removingselectively, after a plating film is precipitated in the through-hole, aregion on the first wiring layer of the plating film.(16) The method of manufacturing the semiconductor unit according to anyone of (9) to (15), wherein the through-electrode includes one of copperand nickel.(17) The method of manufacturing the semiconductor unit according to anyone of (9) to (16), wherein the insulating layer includes one of asilicon oxide film and a photosensitive resin.(18) A solid-state image pickup unit with a semiconductor unit, thesemiconductor unit including:

a first device substrate including a first semiconductor substrate and afirst wiring layer, the first wiring layer being provided on one surfaceside of the first semiconductor substrate;

a second device substrate including a second semiconductor substrate anda second wiring layer, the second device substrate being bonded to thefirst device substrate, and the second wiring layer being provided onone surface side of the second semiconductor substrate;

a through-electrode penetrating the first device substrate and a part orall of the second device substrate, and electrically connecting thefirst wiring layer and the second wiring layer to each other; and

an insulating layer provided in opposition to the through-electrode, andpenetrating one of the first semiconductor substrate and the secondsemiconductor substrate.

(19) The solid-state image pickup unit according to (18), wherein

the first device substrate includes a pixel section, the pixel sectionincluding a photoelectric conversion device as a pixel, and

the second device substrate includes a circuit section that drives thepixel section.

(20) An electronic apparatus with a solid-state image pickup unit, thesolid-state image pickup unit being provided with a semiconductor unit,the semiconductor unit including:

a first device substrate including a first semiconductor substrate and afirst wiring layer, the first wiring layer being provided on one surfaceside of the first semiconductor substrate;

a second device substrate including a second semiconductor substrate anda second wiring layer, the second device substrate being bonded to thefirst device substrate, and the second wiring layer being provided onone surface side of the second semiconductor substrate;

a through-electrode penetrating the first device substrate and a part orall of the second device substrate, and electrically connecting thefirst wiring layer and the second wiring layer to each other; and

an insulating layer provided in opposition to the through-electrode, andpenetrating one of the first semiconductor substrate and the secondsemiconductor substrate.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A semiconductor unit, comprising: a first devicesubstrate including a first semiconductor substrate and a first wiringlayer, wherein the first wiring layer is on one surface side of thefirst semiconductor substrate; a second device substrate including asecond semiconductor substrate and a second wiring layer, wherein thesecond device substrate is bonded to the first device substrate, andwherein the second wiring layer is on one surface side of the secondsemiconductor substrate; a through-electrode that penetrates the firstdevice substrate and a part of the second device substrate in athrough-hole, and electrically connects the first wiring layer and thesecond wiring layer to each other; and an insulating layer, on top ofthe through-electrode in the through-hole, penetrates a part of thefirst device substrate.
 2. The semiconductor unit according to claim 1,wherein the first device substrate is laminated on the second devicesubstrate, the through-electrode fills a first region between the firstwiring layer and the second wiring layer in the through-hole, whereinthe through-hole penetrates from a surface of the first device substrateup to a surface of the second wiring layer through the firstsemiconductor substrate and the first wiring layer, and the insulatinglayer fills a second region on top of the through-electrode in thethrough-hole.
 3. The semiconductor unit according to claim 2, whereinthe first wiring layer is apertured as an opening that configures a partof the through-hole.
 4. The semiconductor unit according to claim 2,wherein an inner wall of the through-hole is entirely covered with ametal thin film.
 5. The semiconductor unit according to claim 2,wherein, of an inner wall of the through-hole, only a third regionopposed to the through-electrode is covered with a metal thin film. 6.The semiconductor unit according to claim 1, wherein thethrough-electrode includes at least one of copper or nickel.
 7. Thesemiconductor unit according to claim 1, wherein the insulating layercomprises at least one of a silicon oxide film or a photosensitiveresin.
 8. The semiconductor unit according to claim 2, furthercomprising a protective film on the first device substrate.
 9. A methodof manufacturing a semiconductor unit, the method comprising: bonding afirst device substrate to a second device substrate, the first devicesubstrate including a first semiconductor substrate and a first wiringlayer, wherein the first wiring layer is on one surface side of thefirst semiconductor substrate, the second device substrate including asecond semiconductor substrate and a second wiring layer, and whereinthe second wiring layer is on one surface side of the secondsemiconductor substrate; forming a through-electrode, thethrough-electrode penetrating the first device substrate and a part ofthe second device substrate in a through-hole, and electricallyconnecting the first wiring layer and the second wiring layer to eachother; and forming an insulating layer, the insulating layer beingformed on the through-electrode in the through-hole and penetrating apart of the first device substrate.
 10. A method of manufacturing asemiconductor unit, the method comprising: bonding a first devicesubstrate to a second device substrate, the first device substrateincluding a first semiconductor substrate and a first wiring layer,wherein the first wiring layer is on one surface side of the firstsemiconductor substrate, the second device substrate including a secondsemiconductor substrate and a second wiring layer, and wherein thesecond wiring layer is on one surface side of the second semiconductorsubstrate; forming, after the bonding the first device substrate to thesecond device substrate, a through-hole penetrating from a surface ofthe first device substrate up to a surface of the second wiring layerthrough the first semiconductor substrate and the first wiring layer,forming a through-electrode, the through-electrode penetrating the firstdevice substrate and a part of the second device substrate, andelectrically connecting the first wiring layer and the second wiringlayer to each other; and forming an insulating layer, the insulatinglayer being formed in opposition to the through-electrode andpenetrating a part of the first device substrate, wherein the formingthe through-electrode includes filling a first region between the firstwiring layer and the second wiring layer in the formed through-hole, andthe forming the insulating layer includes filling, after the forming thethrough-electrode, a second region on the through-electrode in thethrough-hole.
 11. The method of manufacturing the semiconductor unitaccording to claim 10, wherein the forming the through-electrodeincludes electroless plating to form the through-electrode.
 12. Themethod of manufacturing the semiconductor unit according to claim 10,wherein the forming the insulating layer includes: forming, after theforming the through-electrode and the filling the second region on thethrough-electrode in the through-hole, a film of an insulating materialover the first device substrate; and polishing, after the forming thefilm of the insulating material, the film of the insulating material.13. The method of manufacturing the semiconductor unit according toclaim 10, wherein the forming the through-electrode includeselectrolytic plating to form the through-electrode.
 14. The method ofmanufacturing the semiconductor unit according to claim 13, wherein theforming the through-electrode includes stopping the electrolytic platingafter the first wiring layer and the second wiring layer are connectedto each other by a plating film precipitated in the through-hole butbefore the through-hole is filled by the plating film.
 15. The method ofmanufacturing the semiconductor unit according to claim 13, wherein theforming the through-electrode includes removing selectively, after aplating film is precipitated in the through-hole, a region on the firstwiring layer of the plating film.
 16. The method of manufacturing thesemiconductor unit according to claim 9, wherein the through-electrodeincludes at least one of copper or nickel.
 17. The method ofmanufacturing the semiconductor unit according to claim 9, wherein theinsulating layer comprises at least one of a silicon oxide film or aphotosensitive resin.
 18. A solid-state image pickup unit with asemiconductor unit, the semiconductor unit comprising: a first devicesubstrate including a first semiconductor substrate and a first wiringlayer, wherein the first wiring layer is on one surface side of thefirst semiconductor substrate; a second device substrate including asecond semiconductor substrate and a second wiring layer, wherein thesecond device substrate is bonded to the first device substrate, andwherein the second wiring layer is on one surface side of the secondsemiconductor substrate; a through-electrode that penetrates the firstdevice substrate and a part of the second device substrate in athrough-hole, and electrically connects the first wiring layer and thesecond wiring layer to each other; and an insulating layer, on top ofthe through-electrode in the through-hole, penetrates a part of thefirst device substrate.
 19. The solid-state image pickup unit accordingto claim 18, wherein the first device substrate includes a pixelsection, the pixel section including a photoelectric conversion deviceas a pixel, and the second device substrate includes a circuit sectionthat drives the pixel section.
 20. An electronic apparatus with asolid-state image pickup unit, the solid-state image pickup unit is witha semiconductor unit, the semiconductor unit comprising: a first devicesubstrate including a first semiconductor substrate and a first wiringlayer, wherein the first wiring layer is on one surface side of thefirst semiconductor substrate; a second device substrate including asecond semiconductor substrate and a second wiring layer, wherein thesecond device substrate is bonded to the first device substrate, andwherein the second wiring layer is on one surface side of the secondsemiconductor substrate; a through-electrode that penetrates the firstdevice substrate and a part of the second device substrate in athrough-hole, and electrically connects the first wiring layer and thesecond wiring layer to each other; and an insulating layer, on top ofthe through-electrode in the through-hole, penetrates a part of thefirst device substrate.